JPH10332023A - Opening/closing valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an opening/closing valve reducing a fluid leakage amount without enlarging a size. SOLUTION: In a worm gear 21 and a helical tooth 30b of a gear 30, drive force is transmitted from a motor 20 to the gear 30, but a meshing angle is formed without transmitting drive force from the gear 30 to the DC motor 20. A spring 34 is interposed in a drive force transmitting route from the gear 30 to a shaft 32. Even after a valve member is seated in a valve seat, the DC motor 20 is further rotated in a valve closing direction, the spring 34 is wound up, by elastically deforming the spring 34, its energizing force acts in a direction pressing the valve member including a spool 37 to the valve seat. Accordingly, when an opening/closing valve is closed, leaking of vaporized fuel from a contact part between the valve member and the valve seat can be suppressed. Even when the energizing force of the spring 34 acts in a valve opening direction of the gear 30, by locking meshing of the worm gear 21 and the gear 30, even when carrying of a current in the DC motor 20 is turned off, the opening/closing valve is surely closed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-off valve for opening and closing a fluid passage. The present invention relates to an on-off valve connected to a valve.

[0002]

2. Description of the Related Art Conventionally, in an evaporative fuel adsorbing system for adsorbing evaporative fuel generated when an engine is stopped to an canister, for example, an on-off valve is connected to the atmosphere side of the canister in order to communicate or shut off the inside and outside of the canister. In the evaporative fuel adsorption system, the on-off valve is opened during operation of the engine, air is taken in from the outside of the canister, the evaporative fuel captured by the activated carbon of the canister is released, and the released evaporative fuel is sucked into the fuel intake pipe side. Activated carbon for evaporative fuel adsorption is purified. When the engine is stopped, the on-off valve is opened to adsorb the fuel vapor to the activated carbon.

[0003] Here, when the fuel vapor leaks from the contact point between the valve member and the valve seat when the on-off valve connected to the canister is closed, the fuel vapor leaks from the on-off valve to the atmosphere. When the evaporated fuel leaks to the atmosphere, the proportion of the evaporated fuel in the amount of HC discharged from the entire vehicle including HC as an unburned component discharged into the exhaust gas increases. In the current gasoline-powered vehicles, most of the HC discharged from the vehicle is occupied by the evaporated fuel. In today's world where severe restrictions on the amount of HC emissions from vehicles are required, leakage of fuel vapor has become a major problem.

Further, when testing the amount of fuel vapor leakage,
If the fuel vapor leaks from the on-off valve connected to the atmosphere side of the canister, the accuracy of measuring the amount of leakage of the evaporative fuel at locations other than the on-off valve in the evaporative fuel adsorption system decreases.

[0005]

When an on-off valve is constituted by an electromagnetic valve, the valve closing force at the time of closing the valve is increased by increasing the spring constant of a spring for urging the valve member in the valve closing direction. Fuel leakage from the contact point between the valve and the valve member can be reduced. However, if the spring constant of the spring is increased, the size of the solenoid must be increased in order to attract the valve member against the urging force of the spring, so that the size of the on-off valve increases. Also, in the solenoid valve, in order to increase the lift amount of the valve member and increase the fluid flow rate when the valve is opened,
After all, the size of the solenoid must be increased, and there is a problem that the on-off valve becomes large.

In addition, a stepping motor having a large torque is used as a driving source of the valve member, and the valve member is pressed against the valve seat by the driving force of the stepping motor to reduce fuel leakage from a contact portion between the valve seat and the valve member. It is also possible.
However, the stepping motor is expensive and has a problem that the manufacturing cost increases. An object of the present invention is to provide an on-off valve that reduces the amount of fluid leakage without increasing the size.

Another object of the present invention is to provide an inexpensive on-off valve that reduces the amount of fluid leakage without increasing the size. Another object of the present invention is to provide an on-off valve that closes when power is turned off without increasing the size.

[0008]

According to the opening / closing valve according to the first aspect of the present invention, after the valve member is seated on the valve seat, the elastic means is formed by rotating the motor in a direction to press the valve member against the valve seat. It is elastically deformed, and the elastic force of the elastic means is applied in the direction of pressing the valve member against the valve seat. Therefore, since a large elastic force can be applied in the valve closing direction of the valve member, the amount of leakage from the contact portion between the valve seat and the valve member can be reduced.

Further, since the valve member is driven by the motor, the lift amount of the valve member when the valve is opened can be increased without increasing the size of the motor. Therefore, the fluid flow rate at the time of opening the valve can be increased without increasing the size of the on-off valve. According to the opening / closing valve according to the second aspect of the present invention, the driving force transmitting means transmits the driving force in only one direction from the motor to the valve member, so that when the valve is closed, the elastic force of the elastic means moves the motor in the valve opening direction. , The driving force transmitting means is locked, and the motor does not rotate in the valve opening direction. Therefore, the on-off valve can be reliably closed while maintaining the predetermined valve closing force. Furthermore, since the predetermined valve closing force can be maintained even when the power supply to the motor is turned off, an inexpensive DC motor can be used as a drive source, and the manufacturing cost can be reduced.

[0010] According to the on-off valve according to claim 3 of the present invention,
When the valve closing force reaches a predetermined value, the power supply to the motor is turned off, so that the power supply time to the motor can be shortened and the life of the motor can be extended. According to the on-off valve according to the fourth aspect of the present invention, by using a coil spring as the elastic means and disposing the coil spring inside the gear meshing with the motor gear, the on-off valve can be elasticized without extending the axial length of the on-off valve. Means can be assembled.

According to the on-off valve according to claim 5 of the present invention,
The valve member is seated on the valve seat by the urging force of the urging means when the power supply to the motor is turned off. Therefore, the on-off valve closes even when the power supply to the motor is interrupted at the time of failure such as disconnection or failure of the control device. Further, by driving the valve member with the motor, the lift amount of the valve member when the valve is opened can be increased without increasing the size of the motor. Therefore, the fluid flow rate at the time of opening the valve can be increased without increasing the size of the on-off valve.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 shows a schematic diagram of a system in which the on-off valve according to one embodiment of the present invention is used in an on-board diagnosis II (hereinafter, referred to as “OBD-II”) system.
The OBD-II system shown in FIG. 4 includes a pipe 103 that connects the fuel tank 101 and the canister 102, and a pipe 105 that connects the canister 102 and the intake pipe 104.
This is a system for performing a leak check of evaporative emissions generated from the system. An outline of this system configuration will be described.

The fuel tank 101 communicates with a canister 102 via a pipe 103. The pipe 103 is connected to a pressure sensor 107 for detecting a pressure increase after a predetermined time. The canister 102 is connected to the on-off valve 1 and also to one end of a purge valve 108 via a pipe 105. The other end of the purge valve 108 is connected to the intake pipe 104.

In this system, the fuel tank 101
The leak check of evaporative emission generated from the pipes 103 and 105 is performed in the following order. By closing the on-off valve 1 and opening the purge valve 108, a predetermined negative pressure is applied from the intake pipe 104 to the pipe 105 and the pipe 1.
After the introduction, the purge valve 108 is closed to completely shield the evaporative emission. After a certain period of time has passed, a leak check of the evaporative emission is performed by measuring how much the pressure of the pressure sensor 107 has dropped.

Next, the structure of the on-off valve 1 will be described in detail.
As shown in FIG. 2, the on-off valve 1 is a motor-driven electric valve. A fluid passage 100 is formed in the passage member 11 of the on-off valve 1. An inlet 100a of the fluid passage 100 is open to the atmosphere, and an outlet 100b is connected to the canister 102. The passage member 11 on the anti-atmosphere side of the inflow port 100a
Further, a valve seat 11a on which a packing 51 described later is seated is formed. The case 12 is connected to the passage member 1 by bolts 14.
1, and the inside of the case 12 is open to the atmosphere. The support member 13 is sandwiched between the case 12 and the passage member 11. A gear 30 and a shaft 32, which will be described later, are rotatably mounted on the upper end 13a of the support member 13, and use a rod 31 fixed to the case 12 as a rotation axis.

As shown in FIGS. 1 and 2, a semi-circular bearing 30a is formed in the center of a hollow gear 30. The bearing 30a surrounds a rod 31 fixed to the case 12. In. A helical gear 30b is formed on the outer periphery of the gear 30, and the worm gear 21 which rotates together with the DC motor 20 meshes with the helical gear 30b. Electric power is supplied to the DC motor 20 from the connector 22. The worm gear 21 and the helical gear 30 b of the gear 30 are engaged with each other so as to allow only one direction for converting the rotational displacement of the worm gear 21 into the rotational displacement of the gear 30. That is, the gear 30 rotates when the worm gear 21 rotates, but the worm gear 21 does not rotate even if the gear 30 attempts to rotate.

As shown in FIG. 1, a first notch 30c and a second notch 30d are formed in a part of the gear 30 on the valve closing side in a stepwise manner in the circumferential direction. The first notch 30c is the second notch 30d
The notch amount is larger than that. The limit switches 23 and 24 are for detecting the rotation angle of the gear 30. The limit switch 23 is located on the outer periphery of the first notch 30c and the gear 30 on the helical tooth 30b side of the second notch 30d, and the limit switch 24 is located on the outer periphery of the second notch 30d and the gear 30.

The shaft 32 is connected to the locking portion 3 from the gear 30 side.
3, a flange portion 35, and a tooth portion 36 having an external thread formed on the outer peripheral wall are formed in this order. The locking portion 33 is formed in a semicircular shape, and a spring 34 as an elastic means is attached to the ends 33a and 33b of the locking portion 33 so as to embrace the locking portion 33.
Is locked. The spring 34 is constituted by a coil spring. The spring 34 is disposed on the inner peripheral side of the gear 30 and is interposed in a driving force transmission path from the gear 30 to the shaft 32. The bearing 30 a of the gear 30 is located inside the locking portion 33. One end of the bearing 30 a in the circumferential direction abuts against one end of the spring 34 by the rotation of the gear 30, so that the rotational force of the gear 30
2 When the valve is opened as shown in FIG. 2, no urging force is generated in the spring 34.

As shown in FIG. 2, the spool 37 is formed in a cylindrical shape with a bottom, and a small diameter portion is provided from the valve closing side, and a large diameter portion having an outer diameter larger than the small diameter portion is provided in this order. The spool 37 is supported by the support member 13 so as to be able to reciprocate. Since the projection 37a provided on the outer peripheral wall on the opening side of the spool 37 is fitted in the guide groove 13b provided on the support member 13, the rotation of the spool 37 is restricted. As shown in FIG. 1, a female screw 37 b that meshes with a male screw of the tooth portion 36 is formed on the inner peripheral wall of the spool 37. The engagement between the male screw of the shaft 32 and the female screw 37b of the spool 37 is as follows.
The rotation displacement of the shaft 32 and the reciprocal movement of the spool 37 are converted bidirectionally. That is, the rotation of the shaft 32 causes the spool 37 to move into the guide groove 13b.
Reciprocate without rotating along the axis, and the shaft 32 rotates by reciprocating the spool 37. A protrusion 37c formed on the outside of the bottom of the spool 37 is fitted into a recess 50a formed on a plate 50 described later.

Worm gear 21, gear 30, shaft 3
2 and the spool 37 constitute a driving force transmitting means for converting the rotational force of the DC motor 20 into a driving force for reciprocatingly driving the spool 37 in the linear direction and transmitting the driving force. Further, the spool 37, a plate 50 described later, and the packing 51 constitute a valve member. The sealing member 41 is formed of, for example, acrylic rubber, and the supporting member 1 together with the reinforcing plate 40.
3 and the passage member 11. The seal member 41 has two annular lips which are axially separated from each other so as to slide with the spool 37. Since each lip of the seal member 41 abuts on the outer peripheral wall of the spool 37 with elastic force by the ring 42 fitted on the outer periphery of the seal member 41, the seal member 41
Of the fuel vapor from the valve closing direction to the valve opening direction can be prevented.

The rubber packing 51 shown in FIG. 2 is attached to the plate 50 by bonding or the like. Packing 51
An annular contact portion 51a protruding toward the valve closing side is formed on the outer peripheral edge of the valve seat 11a, and the contact portion 51a can be seated on the valve seat 11a. The spring 52 urges the plate 50 toward the valve opening side. Next, the operation of the on-off valve 1 will be described. In the clockwise and counterclockwise directions described below, the DC motor 2
0 and the worm gear 21 indicate the rotation direction in FIGS. 2 and 3, and the other members indicate the rotation directions as viewed from above in FIGS. 1, 2 and 3.

(1) From the valve opening state shown in FIG.
When 0 rotates counterclockwise, the gear 30 rotates counterclockwise due to meshing between the worm gear 21 and the helical gear 30b shown in FIG. As the gear 30 rotates counterclockwise, the bearing 30a comes into contact with the spring 34 locked on the end 33a of the locking portion 33, whereby the rotation of the gear 30 is transmitted to the shaft 32, and the shaft 32 is rotated counterclockwise. Rotate clockwise. When the shaft 32 rotates counterclockwise, the male thread of the tooth part 36 engages with the female thread 37b of the spool 37, so that the projection 37a is guided by the guide groove 13b and the spool 37 does not rotate but resists the urging force of the spring 52. Then, it moves downward in FIG. 2, that is, in the valve closing direction.

When the spool 37 moves in the valve closing direction and the contact portion 51a of the packing 51 is seated on the valve seat 11a, the communication between the inlet 100a and the outlet 100b is interrupted, and the communication between the canister 102 and the atmosphere side. Is shut off. Contact part 5
Even if 1a is seated on the valve seat 11a, the DC motor 20 further rotates, and the bearing 30a winds the spring 34 counterclockwise to elastically deform. The packing 51 is pressed against the valve seat 11a with a larger force from the shaft 32 via the spool 37 and the plate 50 by the elastic force of the wound spring 34, that is, the urging force. As a result, the contact portion 51a is elastically deformed, and the contact portion 51a and the valve seat 11a are deformed.
And the sealing area becomes larger.

The gear 30 is wound while the spring 34 is wound up.
Rotates counterclockwise, and when the limit switch 23 detects the first notch 30c shown in FIG. 1, the power supply to the DC motor 20 is turned off. When the power supply to the DC motor 20 is turned off, the spool 37 moves in the valve opening direction by the urging force of the spring 52, and attempts to rotate the shaft 32 clockwise. However, the meshing of the worm gear 21 and the gear 30 prevents the gear 30 from rotating clockwise, so that the biasing force of the spring 34 is maintained. Therefore, the movement of the spool 37 in the valve opening direction is restricted, so that the packing 51 is kept in contact with the valve seat 11a by a predetermined valve closing force. FIG. 3 shows a closed state of the on-off valve 1 at this time.

(2) From the valve closed state shown in FIG.
0, and when the DC motor 20 is rotated clockwise,
The gear 30 also rotates clockwise. As the gear 30 rotates clockwise, the spring 34 is rewound while the packing 51 is seated on the valve seat 11a. When the spring 34 is rewound, the packing 51 is moved to the valve seat 1.
The valve closing force pressing on 1a decreases.

When the spring 34 is rewound and the bearing 30a shown in FIG. 1 comes into contact with the spring 34 locked to the end 33b of the locking portion, the clockwise rotational force of the gear 30 is transmitted to the shaft 32. Then, the shaft 32 rotates clockwise. When the shaft 32 rotates clockwise,
The spool 37 moves upward in FIG. 3, that is, in the valve opening direction.

When the spool 37 moves in the valve opening direction, the packing 51 and the plate 50 move in the valve opening direction together with the spool 37 by the urging force of the spring 52, and the packing 51 separates from the valve seat 11a. Then, inlet 1
00a communicates with the outlet 100b, and the atmosphere flows from the inlet 100a to the outlet 100b. And outlet 1
At 00b, the atmosphere is supplied to the canister 102, and the fuel vapor is supplied to the intake pipe 104.

The gear 30 further rotates clockwise, and FIG.
When the limit switch 24 shown in FIG. 4 detects the outer peripheral surface of the gear 30 located on the counterclockwise side of the second notch 30d, DC
The power supply to the motor 20 is turned off. At this time, as shown in FIG.
Is pressed against the seal member 41 by the urging force of
It is possible to prevent the fuel vapor from leaking from the fluid passage 100 to the sealing portion between the spool 37 and the sealing member 41.

In the above embodiment showing the embodiment of the present invention described above, even after the packing 51 is seated on the valve seat 11a, the DC motor 20 further rotates in the valve closing direction to wind up the spring 34, and Elastic deformation.
As a result, the urging force of the spring 34 presses the packing 51 against the valve seat 11a.
Is pressed against the valve seat 11a. Therefore, the on-off valve 1
When the valve is closed, the fuel vapor can be prevented from leaking from the contact point between the packing 51 and the valve seat 11a.

Further, in the present embodiment, the engagement between the worm gear 21 and the gear 30 only transmits the rotational force of the DC motor 20 to the gear 30, and even if the gear 30 tries to rotate, the engagement between the worm gear 21 and the gear 30 can occur. Since the engagement is locked, the rotation of the gear 30 is not transmitted to the DC motor 20. In other words, even if the elastic force of the spring 34 wound up by the DC motor 20 presses the packing 51 against the valve seat 11a and acts to rotate the gear 30 in the valve opening direction, the mesh between the worm gear 21 and the gear 30 is reduced. Lock. Therefore, the on-off valve 1 is reliably closed while maintaining the predetermined valve closing force.

Further, when the power supply to the DC motor 20 is turned off, no driving force is generated in the DC motor 20, and even if the urging force of the spring 34 attempts to rotate the gear 30 in the valve opening direction, the worm gear 21 and the gear Since the engagement with the lock 30 is locked, the DC motor 20 does not rotate in the valve opening direction. Therefore, a predetermined valve closing force can be maintained without using a stepping motor, so that the inexpensive DC motor 20 can be used as a drive source as in the present embodiment, and the manufacturing cost can be reduced. Further, since the power supply to the DC motor 20 is turned off when the valve is closed, the operation time of the DC motor 20 is shortened, and the operation life of the DC motor 20 is extended.
However, in the present invention, a stepping motor can be used instead of the DC motor.

In this embodiment, the spring 34 for transmitting the driving force from the gear 30 to the shaft 32 is constituted by a coil spring, and the spring 34 is accommodated in the gear 30 so that the axial length of the on-off valve 1 is extended. And the spring 34 can be assembled without using the same. Coil spring 34
Instead, another elastic member such as a spiral spring may be used.

Although the on-off valve of this embodiment has only two states, that is, valve closing and valve opening, by controlling the power supplied to the DC motor 20, the fluid passage is opened and closed and the flow rate of the fluid passage is controlled. It can also be used as an open / close valve. In the present embodiment, the spool 37 reciprocates as the DC motor 20 rotates in both directions. However, for example, in the present embodiment, the urging direction of the spring 52 for urging the plate 50 in the valve opening direction is changed to the plate 5 in the valve closing direction.
Change to energize 0 and adjust the energizing force.
The spool 37 and the plate 50 are fixed so as to reciprocate integrally. When the gear 30 rotates in the valve opening direction, the engagement angle between the worm gear 21 and the gear 30 of the DC motor 20 is adjusted so that the DC motor 20 also rotates in the valve opening direction when power is turned off. By adopting the above configuration, the on-off valve is closed by the urging force of the spring 52 when the power to the DC motor 20 is turned off, and the power to the DC motor 20 is turned on to attach the plate 50 in the valve closing direction. If the DC motor 20 is rotated in the valve opening direction against the urging force of the urging spring 52, the on-off valve opens. Thus, the valve is opened when the power supply to the DC motor 20 is turned on, and the DC motor 20 is opened.
By configuring the on-off valve to close when the power supply to the motor 20 is turned off, a failure such as a disconnection or a failure of a control device for controlling the power supply to the DC motor occurs, and the DC motor 20
The on-off valve can be closed even when the power cannot be supplied to the switch. Therefore, even when the energization of the DC motor 20 is interrupted by the failure, the on-off valve connected to the atmosphere side of the canister 102 is closed, so that the on-off valve remains open when the on-off valve fails, and the fuel vapor Can be prevented from continuously leaking to the atmosphere.

Further, in the present embodiment, the configuration of the present invention is applied to the on-off valve connected to the atmosphere side of the canister 102 in the evaporative fuel adsorption system. However, it is required that the leakage of the fluid from the fluid passage be substantially zero. It is effective to apply the configuration of the present invention to an on-off valve.

[Brief description of the drawings]

FIG. 1 is an exploded view showing a driving force transmission system of an on-off valve according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view showing an open state of the on-off valve according to the embodiment.

FIG. 3 is a longitudinal sectional view showing a closed state of the on-off valve according to the embodiment.

FIG. 4 is a system schematic diagram in which an on-off valve according to an embodiment of the present invention is applied to an OBD-II system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Opening / closing valve 20 DC motor 21 Worm gear (drive power transmission means) 30 Gear (drive power transmission means) 32 Shaft (drive power transmission means) 34 Spring (elastic means) 37 Spool (drive power transmission means, valve member) 41 Seal member 50 plate (valve member) 51 packing (valve member) 100 fluid passage

Claims (5)

[Claims] A motor, a valve member that opens and closes a fluid passage by being separated from the valve seat and seated on the valve seat; a driving force transmitting unit that transmits a driving force of the motor to the valve member; Elastic means interposed in the driving force transmission path of the driving force transmitting means, the motor being rotated in a direction to press the valve member against the valve seat even after the valve member is seated on the valve seat, and the elasticity is increased. An on-off valve, wherein an elastic force of the elastic means is applied in a direction in which the valve member is pressed against the valve seat by elastically deforming the means. 2. The on-off valve according to claim 1, wherein said driving force transmitting means transmits driving force only in one direction from said motor to said valve member. 3. The on-off valve according to claim 2, wherein the energization of the motor is turned off when a valve closing force for pressing the valve member against the valve seat reaches a predetermined value. 4. The device according to claim 1, wherein the elastic means is a coil spring, and the coil spring is disposed inside a gear that meshes with a motor gear.
2. The on-off valve according to 2 or 3. 5. A valve member which opens and closes a fluid passage by detaching from a valve seat and seating on the valve seat, an urging means for urging the valve member against the valve seat, and an urging means for the urging means. A motor that drives the valve member in a valve opening direction against a biasing force, wherein when the power to the motor is turned off, the valve member is seated on the valve seat by the biasing force of the biasing means. Open / close valve.